Data recording and reproducing method for multi-layered optical disk system

ABSTRACT

A data recording and reproducing method for an optical disk data storage system to record data compressed at different data compression rate according to an operator&#39;s specification, and to reproduce the recorded data by decompressing. According to the operator&#39;s indication, the data is recorded at certain data compression rate in indicated area. The information of the data compression rate and the recorded area is stored as a table of contents (TOC) data. The TOC data is reproduced and stored in a memory after the optical disk is loaded. The recorded data is reproduced by selecting a decoding circuit to decompress the data. The decoding circuit is selected by referring the TOC data to identify data compression rate of the recorded data. Also the TOC data is referred to identify read-in and read-out region of the recorded data. The position of a pick-up when the data recording is started and ended, is recorded as the TOC data to provide random access capability for the data reproduction.

This is a continuation of U.S. patent application Ser. No. 09/370,308,entitled, “DATA RECORDING AND REPRODUCING METHOD FOR MULTI-LAYEREDOPTICAL DISK SYSTEM,” filed on Aug. 9, 1999, now U.S. Pat. No.6,215,743, which is a continuation of U.S. Ser. No. 08/720,531 filed onSep. 30, 1996 entitled, “DATA RECORDING AND REPRODUCING METHOD FORMULTI-LAYERED OPTICAL DISK SYSTEM,” granted on Nov. 9, 1999, now U.S.Pat. No. 5,982,723.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an optical data recording and reproducingmethod. More specifically, this invention relates to an optical diskrecording and reproducing method which makes possible to record dataencoded by different encoding circuit at different data compression rateand to reproduce the data.

2. Description of the prior Art

Initialized by the vast increase in information that needs to beprocessed, optical data storage system having become very importantsystem particularly because of their high storage density per area. Mostof the recent optical information storage systems rotating singleoptical disk are used on which the information is digitally stored inconcentric circular tracks in an ordered, predefined manner to allowchronological fast reading and fast random access to desired pits ofdata.

In order to accomplish even more storage capacity of optical disksystems for enormous information processing, such as video or picturecommunication like so called video-on-demand service, multiple disksystems have been proposed. An optical disk system equipped with two ormore data layers may in theory be accessed as different disks bychanging the focal point with moving lens. Example of this type ofstate-of-the-art include U.S. Pat. No. 5,202,875 issued Apr. 13, 1993 toRosen et al.; Japanese Published Application, 63-276732 published Nov.15, 1988 by Watanabe, et al.

Such a multiple disk recording and reading system is applied to variedoptical disk information storage systems. For example, a digital videodisk (DVD) system for home entertaining is one of the typicalapplication. The mentioned advantage of vast storage capacity maycontribute especially for video signal transmission. In order to recordthe video data efficiently onto the optical disk, a video datacompression technique is one of the key technologies. A standardizedvideo data compression rate has been proposed, which is called MPEG(Moving Picture Experts Group). However, for the home entertainingpurposes, a more flexible function is required. The ability to recorddata at different data compression rates and to reproduce the recordeddata, must be provided.

SUMMARY OF THE INVENTION

The present invention has for its object to provide a multi-layeredoptical disk recording and reproducing system which is able to recorddata encoded by different encoding circuits at different datacompression rates and to reproduce the data by a selected decodingcircuit.

The object of the present invention can be achieved by an optical datarecording and reproducing method, the recording method comprising thesteps of: loading a multi-layered optical disk which has M data layers(wherein M is an integer greater than 1), receiving an operator's signalto record data on an Nth data layer of the multi-layered optical disk ata certain data compression rate (wherein N is an integer greater than 1and not greater than M), operating a routing circuit to transmit thedata to a determined encoding circuit in order to compress the data at apredetermined data compression rate, recording the data on predeterminedposition at the predetermined data compression rate, and rewriting tableof contents (TOC) data to record data about the data compression rate ofthe newly recorded data.

And the object of the present invention also can be achieved by anoptical data recording and reproducing method, the reproducing methodcomprising the steps of: loading a multi-layered optical disk, which hasM data layers (wherein M is an integer greater than 1), reproducing atable of contents (TOC) data recorded in the multi-layered optical disk,storing the reproduced TOC data in a memory, receiving an operator'ssignal to reproduce selected data stored in the multi-layered opticaldisk, referring to the TOC data stored in the memory to identify thedata compression rate of the selected data, and operating a routingcircuit to transmit a readout signal of the selected data to thedetermined encoding circuit in order to decompress the selected data.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an example of an optical data recordingand reproducing apparatus to which the present invention can be applied;

FIG. 2 shows a flowchart for a description of an optical disk recordingmethod of the present invention; and

FIG. 3 shows a flowchart for a description of an optical diskreproducing method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the present invention will be explained with reference tothe drawings.

FIG. 1 shows a block diagram of a first example of an optical datarecording and reproducing apparatus to which the present invention canbe applied. A digital video disk (DVD) 10 which has more than two datalayers is mounted on and secured by a turntable 11 to be rotated by aspindle motor 12. Encoded pits on the DVD 10 are read by a pickup 13which includes a laser diode, a focusing lens, a focusing lens actuator,a tracking actuator and a photo-detector. The movement of the pick-up 13is controlled by a focusing servo circuit 14 and a tracking servocircuit 15.

To reproduce data encoded on the DVD 10, the output signal from thepickup 13 is transmitted to an amplifier 16. According to a focusingerror signal, the focusing servo circuit 14 modulates the focusing lensactuator to move the focal point of the laser beam emitted from thelaser diode by moving the focusing lens, to access one of the data layerof the DVD 10. And according to a tracking error signal, the trackingservo circuit 15 modulates the tracking actuator to control position ofthe pickup 13. The spindle servo circuit 17 modulates the spindle motor12 in order to track linear velocity of the DVD 10.

The detected signal by the pick-up 13 is amplified by the amplifier 16.And the amplified signal is transmitted to a data processing unit 18which is composed of a routing switch 19, an MPEG-2 decoder 20 and a ½decoder 21. The MPEG-2 decoder 20 is a standardized data encoding ordecoding circuit for a Digital Video Disk (DVD), provided in order toencode a data signal for recording on the disk and to decode the readout signal for signal processing. The {fraction (1/2)} decoder 21 is adata encoding or decoding circuit provided to encode and compress theapplied data signal to half data rate of the standardized DVD format.Due to the data compression by the ½ decoder 21, the quality of the datamust be sacrificed in order to record longer data per recording area.However, it makes it possible to provide additional functionality andflexibility for the user. A set of TOC data encoded at a read-in regionof the DVD 10, must include the data indicative of the starting andending position of each data portion, and the data compression rate ofeach data. The TOC data is reproduced right after the DVD is loaded, andthen the each data reproduction is preceded by referring the TOC data.And the TOC data must be rewritten after new data is recorded.

The routing switch 19 is operated by a central processing unit (CPU) 22according to the detected TOC data, which includes the data indicatingthe compression rate of each data to determine the appropriate decodingcircuit. The TOC data is also transmitted to a servo control circuit 23which modulates the focusing servo circuit 14, the tracking servocircuit 15 and the spindle servo circuit 17. The servo control circuit23 modulates each servo circuit to access selected data according to theTOC data which indicates the data indicating the starting and endingpositions of each encoded data portion. Then the decoded signal istransmitted to a signal processor 24 to transmit the reproduced datasignal to any connected unit, such as a display system or sound system.The CPU 22 is operated by an operation signal from a key operating unit26 which transmits all operating signals input by an operator. The CPU22 also controls a display unit 25 to show the operating status of theoperator.

To record data onto the DVD 10, a portion of an input data signal istransmitted from the signal processor 24 to the chosen decoder in thedata processing unit according to the operator's command. The input datasignal is encoded by the selected decoder, then recorded by the pick-up13 which is driven by the each servo circuit and the servo controlcircuit 23. After the new data is recorded on the DVD 10, the TOC datais rewritten to store the data indicating the position and datacompression rate of the newly recorded data.

In addition, by storing the data of read-in and readout position of theall recorded data as TOC data, a capability of quick random access toany data portion is provided for the data reproduction process. Forexample, in order to reproduce one data and another data continuously,the pick-up head can rapidly switch access from readout region of thefirst data to the read-in region of the second data, if data as to allof the read-in region's position is stored and recorded in the TOC data.In the prior art system, all of the read-in region of the data betweenthe first and second data must be counted by detecting the readoutsignal. For example, in order to reproduce both a 4^(th) data elementand a 14^(th) data element recorded on the disk, the pick-up must detectand count ten read-in regions of the data between 4^(th) and 14^(th)data regions by moving the pick-up all over the disk. The presentinvention can provide the advantage of reproducing the data continuouslywithout timelag. The advantage may contribute remarkably to themulti-layered optical disk reading systems which is equipped with morethan two data layers.

FIG. 2 shows a flowchart of operation processing in a central processingunit (CPU), while recording data onto one data layer of a multi-layeredoptical disk. After a multi-layered optical disk which has M data layers(wherein M is an integer greater than 1 ) is loaded, the CPU receives anoperator's signal to record data on the Nth data layer of multi-layeredoptical disk (wherein N is an integer greater than 1 and not greaterthan M). The CPU operates a servo control circuit to dispose a pick-upin order to access read-in region of the data to be recorded (Step1:S1). According to the operator's selection of a data compression rate(S2), the CPU operates a routing circuit to transmit the data thedetermined encoding circuit in order to compress the data at theselected data compression rate (S3). The CPU operates a servo controlcircuit to record the data on a predetermined position at thepredetermined data compression rate (S4). After the data recording iscompleted, the CPU operates a servo control circuit to rewrite a tableof contents (TOC) data to record data indicating the data compressionrate of the newly recorded data (S5).

FIG. 3 shows a flowchart of an operation processing with reference tothe CPU, while reproducing data which is recorded by the proceduredescribed in FIG. 2. After a multi-layered optical disk which has M datalayers, wherein M is an integer greater than 1, is loaded, the CPUoperates the servo control circuit to reproduce table of contents (TOC)data recorded in the multilayered optical disk (S11). Then the CPUstores the reproduced TOC data in a memory (S12). When the CPU receivesan operator's signal to reproduce certain data from the optical disk(S13), the CPU refers to the TOC data stored in the memory to identifythe data compression rate of the selected data (S14). Then the CPUoperates the routing switch to transmit a readout signal of the selecteddata to a determined encoding circuit in order to decompress theselected data (S15). After all of these procedures are completed, thedata reproduction is started.

Although the invention has been particularly shown and described, it iscontemplated that various changes and modification may be made withoutdeparting from the scope of the invention as set forth in the followingclaims.

What is claimed is:
 1. An article comprising an optical disk comprising:a contents data region indicating a layer, a location and a dataencoding technique of recorded data in the optical disk; and a controldata region to read out the recorded data in reference to the layer, thelocation and the data encoding technique.
 2. The article of claim 1,wherein the optical disk comprises a DVD disk.
 3. An article comprisingan optical disk comprising: a first region referenced by a layer and alocation, the first region indicating input data stored on the disk andthe input data being encoded in accordance with a data encodingtechnique; and a physical format information region indicating the dataencoding technique, the layer and the location.
 4. The article of claim3, wherein the physical format information region comprises a table ofcontents.
 5. The article of claim 3, wherein the physical formatinformation region is separate from the first region.
 6. The article ofclaim 3, wherein the optical disk comprises a DVD disk.
 7. An opticaldisk adapted to be coupled to an optical disk drive and usable inassociation with a processor coupled to the optical disk drive, saidoptical disk causing the processor to: i) retrieve a table of contentsdata written on said optical disk; ii) store the retrieved table ofcontents data into a memory; iii) from the table of contents data storedin the memory, identify a data encoding technique and a layer and alocation in which recorded data is stored; iv) read out and route therecorded data at the identified layer and the identified location to adata decoder; and v) decode the read out recorded data in reference tothe identified data encoding technique.
 8. The optical disk of claim 7,wherein the optical disk comprises a DVD disk.
 9. A computer systemcomprising: an optical disk drive adapted to receive an optical disk;and a processor coupled to the optical disk drive and adapted to: i)retrieve a table of contents data written on an optical disk; ii) storethe retrieved table of contents data into a memory; iii) from the tableof contents data stored in the memory, identify a data encodingtechnique and a layer and location in which recorded data is stored; iv)read out and route the recorded data at the identified layer and theidentified location to a data decoder; and v) decode the read outrecorded data in reference to the identified data encoding technique.10. The computer system of claim 9, wherein the optical disk comprises aDVD disk.
 11. A method usable with an optical disk, comprising:recording input data on the optical disk, the input data being encodedwith a data encoding technique and being referenced by a layer andlocation; and recording an indication of the layer, the location and thedata encoding technique in a physical format information region of thedisk.
 12. The method of claim 11, wherein the physical formatinformation region comprises a table of contents.
 13. The method ofclaim 11, wherein the physical format information region is separatefrom a region where the input data is recorded.
 14. The method of claim11, wherein the optical disk comprises a DVD disk.